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[Captain Jack]

Ok, this is my second try at posting this topic, don't have a clue where the first try went!
Anyway...I was reading the post where one of our modellers vessel sank. I began looking at some hull interior pics posted here, and noticed none of them had any "emergency floatation" built in. With all my models, I usually cut to shape, and glue in styrofoam, or some other closed cell foam that was left over from shipping box packing. If the vessel takes on water due to a hull seam opening, drive shaft failure, swamping, or such and fills with water, at least the model won't completely submerge never to be seen again. Any space in the hull that isn't used for radio gear, motors, ect is a good candidate for foam. Also, any superstructure assemblies or parts that aren't permanently affixed usually get a small block of foam added where it can't be seen incase it gets knocked overboard. (it's easier to replace ruined electronics than the whole model).
This addition of floatation material seems like cheap insurance to me!
I'll post some pics in the next block to try to help you visualize my ramblings, as the previous post came back as a "file to large error" and went to the nether reaches of the internet!

[Captain Jack]

example pic one

[Captain Jack]

example two
And please forgive the bits and pieces laying around, this is the Savirile, a work in progress!

[toesupwa]

I began looking at some hull interior pics posted here, and noticed none of them had any "emergency floatation" built in.

Yes, floatation foam is a good idea to aid in recovery of a sinking (or partial sinking) hull... but, remember to allow enough room around the motor, ESC and batteries for cooling air.

[alan colson]

Have heard that if you build something into your model that is likely to seperate from the model if it were to sink attach this to a fishing line or similar. The model can now be located as you have a float on the waters surface. I guess if you use something like dacron with a high breaking strain fixed securely into the hull you may even be able to slowly pull the model to the surface for recovery.
Alan

[roycv]

Hi all, I have a small experience with a sinking.  Not my boat but I was one of the 2 operators at a 24 hour competition and we were sunk by another boat.
We had thought about this and were going to put in a table tennis ball with a line attached, but never got round to it.
It was a steam driven boat and the damage to the boiler, casing and insulation was severe.

The one thing we had not thought of, saved or at least located the boat for us iin 6 feet of water.
It was the line of bubbles coming up from the gas cylinder, obviously a finite source but very effective.

Boat rescued using rowing boat.
regards to all, Roy

[malcolmfrary]

If the hull is big enough, a party pack of balloons will do a good job.  Just inflate then to the point where they have shape, and shove into unseen areas.  Buble wrap works as well. 
Filling a hull with flotation is a truly bad idea - you wind up with a hull that, if it takes any water on board, leaves all your electronics in a small, and theegore rapidly filling, sump.

[Philipsparker]

I built flotation stuff into Tomsk (philsworkbench.blogspot.com/search/label/Tomsk) after sinking the boat the first time I tried pulling a big load practising for our towing competition.

Now I will definitely add polystyrene to future projects. While it may mean the electrics get swamped quicker, at the least the boat sinks slowly so you can recover it. I'd rather replace the radio receiver and a servo (I use waterproof speed controls) than lose the entire model ! Let's face it, once the model in at the bottom of the pond, that radio stuff is lost anyway.

Phil

[Bradley]

The thought crosses my mind that builder's foam - the kind you spray out of a can - would work, especially in closed compartments, as long as you were extremely careful about the amount you spray in to allow for the expansion.  I believe that if you were to inject too much into a closed compartment it could burst the hull and deck apart.  Even if it was sprayed in before the deck was fitted it can easily be trimmed with a sharp knife once it has gone off.  It would be interesting to hear if anyone has tried this method.  :)
Derek.   

[Captain Jack]

Brad, the two part builders foam works, but as you say the expansion is a definate problem. Also, it can trap moisture where you don't want it. Just a few small blocks of properly cut pieces of any closed cell foam will do the trick. If you notice in the pics, I',ve allowed space for what ever water happens to leak in to gather in the low parts of the bilge. Easy to get out, and detectable when there is a problem. Moisture trapped in a fiberglass hull will usually cause delamination after a time, and hence, structural damage. Be aware that the spray in foam can gas off and actually "grow' for several days. I discovered that the hard way.

[cos918]

The thought crosses my mind that builder's foam - the kind you spray out of a can - would work, especially in closed compartments, as long as you were extremely careful about the amount you spray in to allow for the expansion.  I believe that if you were to inject too much into a closed compartment it could burst the hull and deck apart.  Even if it was sprayed in before the deck was fitted it can easily be trimmed with a sharp knife once it has gone off.  It would be interesting to hear if anyone has tried this method.  :)
Derek.   

A friend of mine used that expanding foam. a bit to much and yes the deck was lifted. Another note on this foam is it sticks to surfaces making it a Burger to remove. at work we use this foam to pack bottles for transport. First the bottle is put in to the box. Next a bag is put in to the empty void Between the bottle and the box. The foam is squirted in to the bag and hey presto the foam takes the shape of the bottle. When the foam is dried the bottles wont move and they weight 130kg.
So on a model you could use a freezer bag and squirt the foam in to that. If ever you need to remove this foam is very easy to do as the bag is between the hull and the foam.

john

[Captain Jack]

Let's face it, once the model in at the bottom of the pond, that radio stuff is lost anyway.
My point exactly, sir!

[Shipmate60]

Under NO circumstances fill a sealed compartment with expanding foam.
I have now seen 2 models where the deck has been forced away from the hull.
The foam is full of "bubbles", these will expand with temperature and do.
If you want to use this always leave a good expansion gap betwen the foam and deck.

Bob

[bbdave]

Expanding foam sponges up water and becomes useless fairly quickly. closed cell is much better. But as i've never seen a model boat sink or even sinking i've never bothered